During cardiovascular surgery a patient's heart is temporarily unable to properly oxygenate and circulate blood unaided. Extracorporeal circuits have therefore been developed to provide necessary circulation support. Typically, a venous line drains blood from the right side of the patient's heart and delivers it to a blood reservoir. Blood is then pumped, by a specially designed blood pump, from the outlet of the blood reservoir into a blood oxygenator, for oxygenation and cooling. The oxygenated blood is then delivered via an arterial line to the patient. While the pump is running, the patient returns blood to the venous line to repeat the cycle.
The support circuit normally also includes a blood scavenging sub-circuit for recovering blood from the surgical field to recycle the blood. The scavenging sub-circuit includes one or more suckers (typically two to four) for sucking blood from the surgical field. Vacuum is applied to the suckers by a peristaltic positive displacement pump (also known as a roller pump) or wall vacuum to deliver the scavenged blood to a cardiotomy reservoir. A cardiotomy reservoir includes a defoaming section, because the scavenged blood normally includes a large amount of entrained air, and a filter for filtering the scavenged blood. The outlet for the cardiotomy reservoir delivers the de-foamed, filtered blood to the venous blood reservoir of the main circuit. U.S. Pat. Nos. 3,891,416; 3,993,461; 4,208,193; and 4,243,531 show various cardiotomy reservoirs.
The cardiotomy reservoir may alternatively be an integral portion of the venous blood reservoir, in which the scavenged blood flows through a filter section and the venous blood does not. Both the scavenged blood and venous blood would flow through a defoaming section.
Of course, there are numerous permutations of the basic circuit and sub-circuit, in addition to those described above, that have been employed to provide circulatory support.
Although extracorporeal circuits effectively sustain vital circulatory functions during surgery, it is not uncommon for one of the elements of the system to wear out or fail during a surgical procedure. Most notably, blood oxygenators and reservoirs contain filters and fibrous material that may become damaged or clogged and require replacement. When this occurs the flow of blood in the circuit must be momentarily stopped and the defective elements quickly removed and replaced.
Both time and ease of use are of the essence in making such a change. To facilitate efficient management of the extracorporeal system, especially when an element has failed, it would be advantageous to have a system that is compact and that has elements that may be releasably mounted to each other or to support structures. An apparatus for mounting blood handling devices, such as blood reservoirs and oxygenators, to each other or to support structures would also make it possible to construct extracorporeal circuits that are vertically compressed and flatter. These systems would not only economize on space in the operating room, but would also provide better venous drainage.
U.S. Pat. No. 5,304,164 discloses a bayonet-style mounting apparatus that releasably attaches an oxygenator to a reservoir with pins retained in L-shaped slots.